Madden-Julian Oscillation:

Recent Evolution, Current

Status and Predictions

Update prepared by

Climate Prediction Center / NCEP

September 24, 2012

Outline

• Overview

• Recent Evolution and Current Conditions

• MJO Index Information

• MJO Index Forecasts

• MJO Composites

Overview

Additional potential impacts across the global tropics are available at:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ghazards/index.php

• The latest observations indicate that the MJO continued to weaken as many indicators are now

less coherent as compared to the last couple of weeks. The enhanced phase remained over the

western Pacific.

• The majority of dynamical model MJO index forecasts, however, indicate a larger amplitude

MJO signal emerging across the western Pacific during the upcoming two week period. Model

spread and uncertainty remain somewhat high, similar to last week.

• Based on the latest observations, the MJO is forecast to remain weak, but there is some

potential for a more organized signal to develop across the western Pacific by the beginning of

Week-2.

• The MJO may contribute some to enhanced convection across the western Pacific and perhaps

the eastern Pacific and Central America during Week-2. Suppressed convection is favored for

parts of India, the eastern Indian Ocean and Maritime continent throughout the period. Also,

the chances for tropical cyclogenesis remain elevated across the western Pacific.

850-hPa Vector Wind Anomalies (m s-1)

Note that shading

denotes the zonal

wind anomaly

Blue shades: Easterly

anomalies

Red shades: Westerly

anomalies

The monsoon flow

across the Indian

Ocean and southern

Asia weakened during

the last five days.

Westerly anomalies

persisted over the tropical

Atlantic and western Africa.

Winds across the central Pacific have been near average

during the past five days.

850-hPa Zonal Wind Anomalies (m s-1) Westerly anomalies (orange/red shading)

represent anomalous west-to-east flow

Easterly anomalies (blue shading)

represent anomalous east-to-west flow

The MJO (dashed line) contributed to

westerly anomalies near the Date Line and

across the western hemisphere during

April. Anomalies became more persistent

in most areas during the remainder of

April and May.

Strong westerly anomalies developed

across the eastern Pacific in mid-June and

shifted westward (black solid line) and

contribute to weakening the trade winds.

Easterly anomalies persisted near 80E for

much of August and September.

During September, westerly anomalies

developed near 140E and the easterlies

have decreased near the Date Line.

Time

Longitude

OLR Anomalies – Past 30 days Drier-than-normal conditions, positive

OLR anomalies (yellow/red shading)

Wetter-than-normal conditions, negative

OLR anomalies (blue shading)

In late August into early September,

enhanced convection was observed over

many areas of the northern Indian Ocean,

southern Asia and the western Pacific.

Enhanced convection was also evident

across the eastern Pacific and Caribbean

Sea.

During early-to-mid September, enhanced

convection continued for southern Asia

and parts of the western Pacific while

strong suppressed convection developed

across the eastern equatorial Indian

Ocean. Widespread suppressed convection

was observed over the Americas.

Suppressed convection continued across

the eastern equatorial Indian Ocean and

the Americas while enhanced convection

over the western Pacific generally shifted

northward.

Outgoing Longwave Radiation (OLR)

Anomalies (7.5°S-7.5°N) Drier-than-normal conditions, positive OLR

anomalies (yellow/red shading)

Wetter-than-normal conditions, negative OLR

anomalies (blue shading)

(Courtesy of CAWCR Australia Bureau of

Meteorology)

Time

Longitude

From late May into September, eastward

propagation of both enhanced and suppressed

convection is evident across the eastern

hemisphere (alternating dashed and dotted lines).

Atmospheric Kelvin wave activity also played a

large role in the pattern of anomalous convection

across the Pacific and western Hemisphere

during much of this period, especially June and

July.

During early September, the strongest enhanced

convection shifted eastward to the western

Pacific, just west of Date Line.

200-hPa Velocity Potential

Anomalies (5°S-5°N)

Positive anomalies (brown

shading) indicate unfavorable

conditions for precipitation

Negative anomalies (green

shading) indicate favorable

conditions for precipitation

The MJO strengthened in late January and

continued into mid-April as indicated by

alternating negative (dashed lines) and positive

(dotted lines) anomalies with eastward propagation.

Beginning in late April, anomalies became weaker

and less coherent than earlier in the year.

Eastward propagation was once again evident from

late May into September associated with the MJO,

as well as atmospheric Kelvin wave activity, which

at times resulted in fast eastward propagation of

observed anomalies.

In mid-September, anomalies decreased and

eastward propagation less clear.

Time

Longitude

IR Temperatures (K) / 200-hPa

Velocity Potential Anomalies

Positive anomalies (brown

contours) indicate unfavorable

conditions for precipitation

Negative anomalies (green

contours) indicate favorable

conditions for precipitation

The large scale velocity potential pattern reflects anomalous upper-level convergence across the Americas

and the Atlantic with smaller areas of anomalous upper-level divergence over Africa, the Indian ocean and

parts of the Pacific.

200-hPa Vector Wind Anomalies (m s-1) Note that shading denotes the

zonal wind anomaly

Blue shades: Easterly anomalies

Red shades: Westerly anomalies

Westerly anomalies (blue

boxes) decreased considerably

during the past five days over

the eastern Pacific and

Americas.

200-hPa Zonal Wind Anomalies (m s-1) Westerly anomalies (orange/red

shading) represent anomalous west-to-

east flow

Easterly anomalies (blue shading)

represent anomalous east-to-west flow

The MJO contributed to alternating

westerly (dotted lines) and easterly

(dashed lines) anomalies into mid-April.

Anomalies were less coherent during

much of April and May as the MJO was

weak.

Westerly anomalies shifted eastward

across the Pacific during July and early

August.

Westerly anomalies increased markedly

across the eastern Pacific in early

September and have persisted .

Time

Longitude

Weekly Heat Content Evolution

in the Equatorial Pacific

Time

Longitude

From July 2011 through February 2012,

heat content was below average in the

central and eastern equatorial Pacific.

From March into July 2012, heat content

anomalies became positive and increased

in magnitude across eastern equatorial

Pacific, partly in association with a

downwelling Kelvin wave.

Positive anomalies decreased across the

eastern Pacific during late August and

September.

MJO Index -- Information

• The MJO index illustrated on the next several slides is the CPC version of the

Wheeler and Hendon index (2004, hereafter WH2004).

Wheeler M. and H. Hendon, 2004: An All-Season Real-Time Multivariate MJO Index:

Development of an Index for Monitoring and Prediction, Monthly Weather Review, 132, 1917-1932.

• The methodology is very similar to that described in WH2004 but does not

include the linear removal of ENSO variability associated with a sea surface

temperature index. The methodology is consistent with that outlined by the

U.S. CLIVAR MJO Working Group.

Gottschalck et al. 2010: A Framework for Assessing Operational Madden-Julian Oscillation

Forecasts: A CLIVAR MJO Working Group Project, Bull. Amer. Met. Soc., 91, 1247-1258.

• The index is based on a combined Empirical Orthogonal Function (EOF)

analysis using fields of near-equatorially-averaged 850-hPa and 200-hPa zonal

wind and outgoing longwave radiation (OLR).

MJO Index -- Recent Evolution

The MJO index amplitude remained

low during the past week with no

eastward propagation.

The axes (RMM1 and RMM2) represent daily values of the principal components from the two

leading modes

The triangular areas indicate the location of the

enhanced phase of the MJO

Counter-clockwise motion is indicative of

eastward propagation. Large dot most recent

observation.

Distance from the origin is proportional to MJO

strength

Line colors distinguish different months

MJO Index – Historical Daily Time Series

Time series of daily MJO index amplitude from 1997 to present.

Plots put current MJO activity in historical context.

Ensemble GFS (GEFS) MJO Forecast

RMM1 and RMM2 values for the most recent

40 days and forecasts from the ensemble Global

Forecast System (GEFS) for the next 15 days

light gray shading: 90% of forecasts

dark gray shading: 50% of forecasts

Yellow Lines – 20 Individual Members

Green Line – Ensemble Mean

The ensemble GFS forecasts the MJO signal

to increase in amplitude with some eastward

propagation during the next two weeks.

The ensemble mean GFS forecast indicates

enhanced (suppressed) convection developing across

the western Pacific (Indian Ocean) mainly during

Week-2.

Ensemble Mean GFS MJO Forecast

Spatial map of OLR anomalies for the next 15 days Time-longitude section of (7.5°S-7.5°N) OLR anomalies

for the last 180 days and for the next 15 days

Figures below show MJO associated OLR anomalies only (reconstructed from RMM1 and

RMM2) and do not include contributions from other modes (i.e., ENSO, monsoons, etc.)

Constructed Analog (CA) MJO Forecast Figure below shows MJO associated OLR anomalies only (reconstructed from RMM1 and

RMM2) and do not include contributions from other modes (i.e., ENSO, monsoons, etc.)

Spatial map of OLR anomalies for the next 15 days Time-longitude section of (7.5°S-7.5°N) OLR anomalies

for the last 180 days and for the next 15 days

The forecast indicates weak anomalous

convection during the next two weeks.

MJO Composites – Global Tropics Precipitation Anomalies (May-Sep) 850-hPa Velocity Potential and

Wind Anomalies (May-Sep)

U.S. MJO Composites – Temperature

Zhou et al. (2011): A composite study of the MJO influence on the surface air temperature and

precipitation over the Continental United States, Climate Dynamics, 1-13, doi: 10.1007/s00382-011-

1001-9

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml

Left hand side plots show temperature anomalies by

MJO phase for MJO events

that have occurred over the

three month period in the

historical record. Blue

(orange) shades show

negative (positive) anomalies

respectively.

Right hand side plots show

a measure of significance for

the left hand side anomalies.

Purple shades indicate areas

in which the anomalies are

significant at the 95% or

better confidence level.

U.S. MJO Composites – Precipitation

Zhou et al. (2011): A composite study of the MJO influence on the surface air temperature and

precipitation over the Continental United States, Climate Dynamics, 1-13, doi: 10.1007/s00382-011-

1001-9

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml

Left hand side plots show precipitation anomalies by

MJO phase for MJO events

that have occurred over the

three month period in the

historical record. Brown

(green) shades show negative

(positive) anomalies

respectively.

Right hand side plots show

a measure of significance for

the left hand side anomalies.

Purple shades indicate areas

in which the anomalies are

significant at the 95% or

better confidence level.